1. Field of the Invention
The present invention relates to an apparatus and method for digital auto-focus, and, more particularly, to an apparatus and method for digital auto-focus by image processing, rather than by a mechanical method in which a position of a lens for obtaining an image is shifted.
2. Description of the Related Art
Most commercial image-capture devices employ a variety of auto-focusing (AF) systems.
Adjustment methods of auto-focusing (AF) employed in conventional image-capture devices are broadly classified into two types: infrared auto-focusing (IRAF) and semi-digital auto-focusing (SDAF). In IRAF, a focus is accurately detected by an analysis module using a return distance of a wavelength, and the focus is adjusted by a control module by moving a position of a lens using a focus detection result provided from the analysis module. In SDAF, high-frequency components are calculated by an analysis module to accurately detect a focus and the focus is adjusted by a control module by moving a position of a lens, similar to IRAF.
The mechanically adjusting of the lens by shifting the lens in this way, however, involves limitations in the position and range of DoF (Depth of Focus), for setting the focus according to the lens characteristic and lens ranging.
Accordingly, the present invention proposes a fully digital auto-focusing (FDAF), in which the position and range of DoF can be adjusted by image processing without driving a lens.